update `CHANGELOG.md` for v3.2.0 [ci skip]
update `CHANGELOG.md` for v3.2.0 [ci skip]

boneskull/mocha,hoverduck/mocha,rlugojr/mocha,boneskull/mocha,mochajs/mocha,beatfactor/mocha,rlugojr/mocha,mochajs/mocha,rlugojr/mocha,apkiernan/mocha,villesau/mocha,igwejk/mocha,nightwatchjs/mocha-nightwatch,nightwatchjs/mocha-nightwatch,menelaos/mocha-solarized,JohnnyEstilles/mocha,hoverduck/mocha,villesau/mocha,nightwatchjs/mocha-nightwatch,boneskull/mocha,menelaos/mocha-solarized,JohnnyEstilles/mocha,igwejk/mocha,hoverduck/mocha,apkiernan/mocha,beatfactor/mocha,outsideris/mocha,sul4bh/mocha,hoverduck/mocha,adamgruber/mocha,outsideris/mocha,adamgruber/mocha,adamgruber/mocha,menelaos/mocha-solarized,beatfactor/mocha,sul4bh/mocha,villesau/mocha,sul4bh/mocha,apkiernan/mocha,JohnnyEstilles/mocha,mochajs/mocha